Rust is a deposit of iron oxide that forms on the surface of the metal iron. It makes the item a dark, dull, dark reddish brown with a mottled surface. Iron is very susceptible to corrosion – the surface of the iron reacts with oxygen in the air and this reaction is faster and more intense in damp conditions.
If the rust is not too deep it can be removed using a commercial rust remover. This is made up of a solution of phosphoric acid. The acid reacts quickly with the iron oxide, converting it to soluble iron phosphate. Because the acid is weak, it does not react very readily with the iron itself, so the reaction stops when the acid reaches the pure metal.
If the iron object is then rinsed well in water to remove the soluble iron phosphate, the clean metal then shows through, restoring the shine of the native iron.
If the rust is not too deep it can be removed using a commercial rust remover. This is made up of a solution of phosphoric acid. The acid reacts quickly with the iron oxide, converting it to soluble iron phosphate. Because the acid is weak, it does not react very readily with the iron itself, so the reaction stops when the acid reaches the pure metal.
If the iron object is then rinsed well in water to remove the soluble iron phosphate, the clean metal then shows through, restoring the shine of the native iron.